This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The aim of this proposal is to study solute transport mechanisms in bacterial and eukaryotic cells by x-ray crystallography. One of our projects is the crystallization of eukaryotic facilitated glucose transporter, which was supported by NIH Exploratory/Developmental Research Grant Program R21. Glut1, a member of the Major Facilitator Superfamily, is an extensively studied representative of these facilitated transporters. Glut4 is responsible for insulin-regulated glucose disposal. Several diseases have been identified with mutations resulting in malfunction of Gluts, such as GLUT1 deficiency syndrome and type II diabetes. GLUT1 has been shown to overexpress in few cancer cells. It is important to obtain a high-resolution structure, as well as to characterize the transport mechanism at an atomic level. Thus far, there is no 3-D crystal structure available for any glucose facilitator. We directly isolate GLUT1 from human Red Blood Cells membranes. Initial crystallization using a high throughput robotic approach is being carried out.